St-Pierre, who vacated his title in late 2013 but had recently hinted at a possible return this year, underwent his second ACL surgery today, this time for his left knee. Dr. Neal ElAttrache of Los Angeles’ Kerlan-Jobe Orthopedic Clinic, who performed the surgery, also repaired St-Pierre’s right knee when he tore his ACL in 2011.

St-Pierre (25-2 MMA, 19-2 UFC) spent 19 months on the bench after tearing his right ACL while training for a fight with Carlos Condit at UFC 137. He returned at UFC 154 to dominate Condit en route to a unanimous-decision win.

The latest procedure means St-Pierre won’t return to the cage before year’s end. During his recent absence, Johny Hendricks defeated Robbie Lawler to win the title that St-Pierre held during a legendary title reign from 2008-2013.

For more on the UFC’s upcoming schedule, stay tuned to the UFC Rumors section of the site.

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Before he injured his knee, hear what some of GSP’s fellow fighters had to say about whether or not he should return from his self-imposed hiatus.

TORONTO – MMAjunkie is on scene and reporting live from today’s early and official UFC 206 fighter weigh-ins, which kick off at 9 a.m. ET (6 a.m. PT). Join us for a live video stream and official results.

ALBANY, N.Y. – MMAjunkie is on scene and reporting live from today’s UFC Fight Night 102 event at Times Union Center in Albany, N.Y., which kicks off at 5:45 p.m. ET (2:45 p.m. PT). You can discuss the event here.